How to change the background color for JPanels with Nimbus Look and Feel?

Question

I want to use a different background color for all my JPanels in an application. How can I do that when using Nimbus Look and Feel?

I follow Changing the Color Theme to change the color of components in Nimbus Look and Feel.

It only works sometimes, randomly. If I set a PropertyChagneListener before I change the color, it is only notified once.

Here is some test code:

public class RedPanels extends JFrame {

  public RedPanels() {
    JPanel panel = new JPanel();
    add(panel);
    setPreferredSize(new Dimension(100, 100));
    pack();
    setVisible(true);
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

      @Override
      public void run() {

        try {
          for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                UIManager.setLookAndFeel(info.getClassName());
                UIManager.getDefaults().addPropertyChangeListener(
                                               new PropertyChangeListener() {

                  @Override
                  public void propertyChange(PropertyChangeEvent event) {
                    if (event.getPropertyName().equals("Panel.background")) {
                      System.out.println("color changed");
                    }

                });
                UIManager.put("Panel.background", new Color(255,0,0));
                break;
            }
          }
        } catch (Exception e) {
            // Nimbus is not available.
        }
        new RedPanels();
        }
    });
  }
}

Answer 1

UIManager.getLookAndFeelDefaults().put("Panel.background", Color.RED);

Answer 2

there are three ways

1) override nimbusBase for set DerivedColor

2) create own Painter, only one example is there -> aephyr codesource,

3) simple and dirty hack to set the Color directly

import java.awt.*;
import javax.swing.*;
import javax.swing.border.LineBorder;

public class NimbusJPanelBackGround {

    public NimbusJPanelBackGround() {
        JPanel p = new JPanel();
        UIDefaults nimbusOverrides = new UIDefaults();
        nimbusOverrides.put("Panel.background", Color.blue);
        p.putClientProperty("Nimbus.Overrides", nimbusOverrides);
        SwingUtilities.updateComponentTreeUI(p);

        JPanel p1 = new JPanel();
        nimbusOverrides = new UIDefaults();
        nimbusOverrides.put("Panel.background", Color.green);
        p1.putClientProperty("Nimbus.Overrides", nimbusOverrides);
        SwingUtilities.updateComponentTreeUI(p1);
        p1.setBorder(new LineBorder(Color.black, 1));

        JPanel p2 = new JPanel();
        nimbusOverrides = new UIDefaults();
        nimbusOverrides.put("Panel.background", Color.ORANGE);
        p2.putClientProperty("Nimbus.Overrides", nimbusOverrides);
        SwingUtilities.updateComponentTreeUI(p2);

        JFrame f = new JFrame();
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        f.add(p, BorderLayout.NORTH);
        f.add(p1, BorderLayout.CENTER);
        f.add(p2, BorderLayout.SOUTH);
        f.setSize(200, 100);
        f.setLocation(150, 150);
        f.setVisible(true);
    }

    public static void main(String[] args) {

        try {
            for (UIManager.LookAndFeelInfo laf : UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(laf.getName())) {
                    UIManager.setLookAndFeel(laf.getClassName());
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                NimbusJPanelBackGround nimbusJPanelBackGround = new NimbusJPanelBackGround();
            }
        });
    }
}